1. Field of the Invention
The present invention relates to a bearing and, more particularly, to a thrust bearing which comprises foils subjected to a friction with gas, and is equipped in a turbo compressor to support a rotational shaft in an axial direction of the rotational shaft.
2. Description of the Related Art
Generally, compressors are used to compress gas, such as air or refrigerant gas. Among the compressors, a turbo compressor forces an impeller to rotate by virtue of a driving force of a motor, and then, intakes and compresses gas with a centrifugal force generated by a rotation of the impeller.
As for components acting to support the rotational shaft, bearings can be classified into a radial bearing and a thrust bearing according to a direction of a load applied to the shaft. As is disclosed in Korean Patent Registration No. 10-0399325, the turbo compressor is provided with the radial bearing and the thrust bearing to support the rotational shaft.
Referring to FIG. 1, a conventional thrust bearing 30 has a configuration wherein several elastic foils 31 overlap each other on one side of a disk-shaped base 33 having an opening 30a formed at the center thereof, so that the elastic foils 31 contact a disk, not shown, equipped to a rotational shaft, not shown. When a predetermined period is passed after a rotation of the rotational shaft, a gaseous film is formed between the disk and the elastic foils 31, so that the disk is spaced a predetermined distance from the elastic foils 31.
However, according to the conventional bearing 30, when increasing the stiffness of the elastic foils 31 in order to enhance the load capacity of the bearing 30, the gaseous film is formed between the disk and the elastic foils 31, lowering the separating speed of the disk from the elastic foils. As a result, a great amount of friction is generated between the disk and the elastic foils 31, resulting in damage to a surface of the elastic foils and a mechanical malfunction of the turbo compressor.